Vitreous glass sealed beam lamp units have been used for vehicle lighting since at least the 1930's in the United States. These lamps generally include a paraboloidal reflector having a highly mirrorized inner surface that usually has two central openings that receive connectors for a filament aligned within the reflector. The reflector is enclosed by a circular convex lens also constructed of glass that is located with respect to the reflector by various types of integral locating tabs and is joined to the reflector by heat fusion. The connector assemblies are also usually connected to the reflector by a heat fusion process, and the composition and pressure of gas within the reflector-lens envelope are carefully controlled through a filling tube formed integrally with the reflector, and this tube is fused after evacuation and/or, inert gas filling of the lamp envelope. Controlling the atmosphere within the envelope through the filling tube is extremely costly, and the filling tube must be carefully fused at the proper instant to achieve the desired atmosphere within the envelope.
Such a sealed beam lamp unit is shown and described in the D. K. Right U.S. Pat. No. 2,147,314 dated Feb. 21, 1939.
These sealed beam lamp units, which must be replaced after the filaments burn out, require complicated locking rings and adjustment assemblies, permanently carried by the associated vehicle to hold them in proper position. The locking rings frequently include adjusting brackets for varying the attitude of the lamp units to properly adjust the lamp's beam to effect the desired lamp alignment.
It has been suggested that the reflector of a rectangular sealed beam lamp unit be constructed of a plastic material with support flanges formed integrally with the plastic to eliminate the complicated mounting flanges and rings required in prior lamp units. Such a construction is shown in the Thomas T. Talon et al U.S. Pat. No. 4,188,655. This patent discloses a lamp with three integral flanges on a plastic reflector that cooperate with three adjusting assemblies mounted to the vehicle that permit adjustment of the lamp beam in two orthogonal planes. While such an arrangement is suitable for many passenger automobile applications it is nevertheless quite costly because of the three separate fastening and adjusting mechanisms required.
Another problem found in the manufacture of glass sealed beam lamp units is the difficulty in aligning the filament with the paraboloidal mirrorized reflector surface. Since the filament connector assembly is fused into the rear of the reflector, the fusion process itself frequently causes misalignment of the connector and the filament. Therefore, in sealed beam lamp units manufactured using this fusion technique it is necessary that the filaments be realigned after the fusion process has been completed. One attempt in the past to ameliorate this misalignment problem in vitreous glass lamp units has been to form the vitreous reflector with an enlarged opening in the rear and separately form a vitreous holder for the filament and connector assembly. The filament and connector assembly is then fused into the vitreous holder and the filament is aligned with respect to certain locating surfaces on the vitreous holder. Thereafter the holder and aligned filament are fused into the reflector. While this process has simplified the alignment of the filament it is also very costly because of the additional filament holder and the additional fusion of the holder to the reflector.
A still further problem in these vitreous lamp units is the difficulty in attaching the terminals to the rear of the vitreous reflectors. Heat fusion of the terminals is difficult and exacerbates the connector misalignment problem.
It is a primary object of the present invention to ameliorate the problems noted above in sealed beam lamp units.